Known is an image-forming method for obtaining a color image by subjecting a photographic material (which has on a support at least three silver halide light-sensitive layers each containing a silver halide emulsion which is color-sensitized so that it may be selectively sensitive to any of three lights emitted from a semiconductor laser or a light-emitting diode and each containing a color image-forming color coupler), to scanning exposure of three different lights each having a different wavelength and then processing the exposed material for color development to form a color image on the material. Also known are the photographic materials which are employed for the method. For instance, the method and materials are illustrated in detail in JP-A-55-13505, JP-A-61-137149, JP A-62-295648 and JP-A-63-197947 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") and in Reports in 4th International Conference (SPSE) of Non-Impact Printing (NIP), pages 245 to 247.
However, if a good full-color image is to be obtained by the method illustrated in the above-mentioned publications or literature, a relatively long development procedure is required. Therefore, the known method is inconvenient for rapidly and continuously forming a full-color image of high quality by employing a high-speed scanning exposure system. One reason is probably the high silver bromide content in the photographic emulsion of the photographic material, which requires a long period of time for the respective development, bleaching and fixation steps. In order to overcome the problem, an emulsion having a high silver chloride content might be recommended. Another reason is that a long time is required to decolor the dye which has been added for the purpose of absorbing a light of a particular wavelength to prevent color mixing in the photographic material or for the purpose of absorbing the unnecessary scattering or reflecting light in the hydrophilic colloid layer in the photographic material. Although images could be formed in the absence of such dye, such an image has poorer image characteristics, such as a lowered dissolving power. Accordingly, addition of the dye is essential to obtain images of high quality. Therefore, it is desired to employ such as a dye that may easily be decomposed during development to be decolored to that may easily be dissolved out of the photographic material after photographic processing.
It is required that the photographic dye have not only the above-mentioned easy decolorability but also a sufficient stability during storage without having a bad effect on the silver halide grains to reduce the photographic property of the photographic material. It has heretofore been difficult to obtain photographic dyes which satisfy all these requirements. In addition, this technical field has lately required further acceleration of the speed of photographic processing, and accordingly, finding appropriate dyes which satisfy this need is increasingly difficult.
Even though there is a dye which can resolve the above problems, it is expected based on the finding of a conventional photographic image formation using a surface exposure (not a scanning exposure) that remarkable decrease in sensitivity derived from light absorption inevitably occurs by addition of the dye, while the preferred effects increase.
On the other hand, it is know that where the processing conditions are made more severe by varying the temperature, the pH value and the composition of the photographic solution for the purpose of accelerating the photographic processing speed, the photographic property of the processed photographic material frequently worsens. In particular, where a high silver chloride emulsion having a silver chloride content of 90 mol% or more is employed, it is found that the processed photographic material is often fogged to have so-called high-density streaks induced by pressure applicaton. It may be presumed that such streaks are caused by the contact of the photographic material being processed with the roller or the like in the developer tank in an automatic developing machine whereupon the contacted portion of the photographic material is scratched and is over-sensitized under pressure.